docs: def com_google_fonts_check_metadata_valid_filename_values(font,
                                                            family_metadata):
    """METADATA.pb font.filename field contains font name in right format?"""
    expected = os.path.basename(font)
    failed = True
    for font_metadata in family_metadata.fonts:
      if font_metadata.filename == expected:
        failed = False
        yield PASS, ("METADATA.pb filename field contains"
                     " font name in right format.")
        break
    if failed:
      yield FAIL, ("None of the METADATA.pb filename fields match"
                  f" correct font name format (\"{expected}\").")